Ok i put some 24s on my 06 f150 and it murdered the gas mileage. i know its the rims that done it, i was wondering if i regeared the rearend if it would help bring my mileage back up some. I have 3:55 now and im wondering if 3:73 would help out. It is mostly city miles but once a month take a 400 mile trip one way, so 800 round trip. I am currently getting about 10 in the city and about 14 on the highway. I need some improvement. Already have exhaust and CAI and tuner. Any help would be appreciated.And the tire size is 295/35/24, it is equal to a 32 in tall tire.

 

No, you need to go higher (or lower if you look at it that way). I have 3.73 gears and I get about 13-14 mixed driving. When I get back from my next deployment I am going to 4.30 or 4.56 gears. That should do it for me. But you will waste your money for very little returns on 3.73 gears. But to be honest, the MPG's are gonna stay lower, your rims and tires weigh about 105-110 pounds each, while the stockers weight 65 pds each (that is for 18's) that is a lot of added rotational unsprung weight. The main thing I want to inprove is acceleration, but the lower gearing should help a little with the city mpg's.

 

Your overall diameter stayed the same?

What is killing your mileage is the WEIGHT of your wheel/tires... Take one tire/wheel off and weigh the beast. I bet it's way over 100lbs. Some smaller diameter 1 piece billet wheels will not only save you weight, but also give you some more sidewall for a smoother ride.

I beleive my factory steel wheels with slightly smaller tires weighed in roughly at 73lbs. Factory tires I imagine is around 80lbs+ My billet 20" centerlines with 295/45/20 weigh in at 63lbs. A rough estimate is every 10lbs of un-sprung weight equals 100lbs of sprung weight. So if you wheel tire package weighs 120lbs a piece, over the factory 80. It's like you are carrying an additional 1600lbs of weight. Seems ridiculous I know, but that makes sense on why your gas mileage is so low doesn't it?

Gears will help around town, 4.11's or 4.30's would be a good gear for 32" tires.

What exhaust?
What tuner?
What CAI?

10MPG though out of regular cab pickup like yours even with those wheels tells me two things... Either you have a problem with your truck, or a problem with your right foot.

Don't go above 2000rpm's driving around town, stay under that rpm if possible. Coast to stop lights, avoid hard braking and accelerating. Use your cruise control on the highway.

My blown 5.4 has been getting 12-13 around town(with some spirited driving, still can't keep my foot out of it) and 17-19 on the highway, depending on how fast I drive.

 

Yea i have a slight problem with my right foot. And i think the diameter styed the same, maybe half in bigger than stock,not real sure. Even with the stock tire it was only getting 12 or 13 in city and maybe 16 or 1 on highway. I messed up when i got the truck it has the 4.6,shoulda got the 5.4. O well. I have true duals with x pipe, Flowmaster of coarse. K&N intake system, and super chips programmer. I bought the super chip because it works with my stang also. But i want to know how much of an increase i could expect out of some gears, with average driving, No lead foot.

 

I would get some custom tunes either from Gryphon or VMP especially because your running a cold air intake and also running duals with an X pipe. With the custom tunes you will be able to get the most out of each of those, and you can also request to him that you want to get better gas milage.. I would think that would help you out alot.

 

So you did increase the diameter of the rubber that meets the road ... which means you are operating at lower engine RPMs/lower on the power curve .... which gives you more of a sluggish feel off the line ... which you try to compensate for with more foot input. This is the main draw back to larger diameter tires.

Regearing will allow the engine RPMs to come up quicker, to deliver more power to the wheels faster.

 

I got 24's on my truck in the spring/summer and I swear its the same if not better than the stock 20's?

 

That is odd. You have the specs of both sets? Not calling you a liar, I am looking at a set of stock 20's and wonder if there is a huge weight difference

 

That is odd. You have the specs of both sets? Not calling you a liar, I am looking at a set of stock 20's and wonder if there is a huge weight difference

 

I'd be worried about the brakes not being the proper size with 24's.

 

Is there a mandatory size brake to have with 24's I would upgrade but I have 18's as my winter wheels and really can't go bigger. Upgraded pads and rotors are gonna happen when these wear out.